Nanoclay (NC) reinforced high-density polyethylene (HDPE) composites were prepared by different melt compounding methods using (1) a single screw extruder (SSE), (2) twin screw extruder (TSE), (3) a combination of SSE and extensional flow mixer (EFM), and (4) a bowl mixer masterbatch method (MB). PE-grafted maleic anhydride (PE-eta-MA) was used as a compatibilizer. EFM increased complex melt viscosity (eta*) of the HDPE/NC composites as compared to the neat HDPE and also provided a better interaction between HDPE and NC to create slightly lower melt eta* as compared to MB and PE-g-MA composites. The low viscosity melt behavior of the pure HDPE changes to more solid like melt behavior in the PE-eta-MA HDPE/NC composites in the low frequency (omega) region. PE-eta-MA1EFM method exhibited better impact strength compared to the other HDPE/NC composites. Using the PE-eta-MA and masterbatch compounding methods had a beneficial role in improving mechanical properties. (C) 2016 Society of Plastics Engineers